q: double on stack

[sapero]

I'm writting wmi scripting wrapper class: connecting, requesting, selecting and requesting/changing properties is done and works like in vbs.
Now is time for executing methods. I have used class method of CDECL type, so variable number of arguments can be passed.

Arguments from stack are copied into VARIANT structure, strings and int's are no problem.
I'm not sure about float and double:
what i think:
- usage (pushing) of float is same as for int, string (4 bytes)
- double - pointer to double is pushed onto stack

also this it the important bit of my method:

Code Select Expand

CSWbemObject :: ExecMethod(/*MethodName, arguments*/...),heap
{
ÂÃ,  int argc = va_count()-1;
ÂÃ,  void *arg = va_start(this);
...
ÂÃ,  VARIANT vArg;
ÂÃ,  wbemCimtypeEnum cim;
...
ÂÃ,  vArg.vt = cim;ÂÃ,  // ISWbemProperty property->get_CIMType(&cim);

ÂÃ,  vArg.intVal = *(int)arg; // as default for byte/word/int (and float ?)
ÂÃ,  if (cim = wbemCimtypeString)
ÂÃ,  ÂÃ,  vArg.bstrVal = SysAllocString(a2w(*(string)*(pointer)arg)); // ok

ÂÃ,  if (cim = wbemCimtypeReal32) vArg.fltVal = *(float)arg;ÂÃ,  // i hope this can be removed

ÂÃ,  // double
ÂÃ,  if (cim = wbemCimtypeReal64) vArg.dblVal = *(double)*(pointer)arg;

ÂÃ,  property->put_Value(vArg);
ÂÃ,  VariantClear(vArg);
...

}
Am i correct?

Question: is someone interested in Aurora like scripting wmi?
vbs:

Code Select Expand

Set objWMIService = GetObject("winmgmts:" & "!\\" & strComputer & "\root\cimv2")
Set colFiles = objWMIService.ExecQuery ("Select * from CIM_DataFile where Name = 'c:\\wmirenametest.vbs'")
For Each objFile in colFiles
ÂÃ,  ÂÃ,  errResult = objFile.Rename("c:\scripts\toggle_service.old")
Next
aurora:

Code Select Expand

CSWbemServices root;

CSWbemServices *objWMIService = root.GetObject("winmgmts:!\\\\.\\root\\cimv2");
if (objWMIService)
{
CSWbemObjectSet *colFiles = objWMIService->ExecQuery(
"Select * from CIM_DataFile where Name = 'c:\\\\wmirenametest.vbs'");

if (colFiles)
{
CSWbemObject *objFile = colFiles->ForEach();
while (objFile)
{
string sret = objFile->ExecMethod("Rename", "c:\\wmirenametest.old");

delete objFile;
objFile = colFiles->ForEach();
}
delete colFiles;
}
delete objWMIService;
}

[Ionic Wind Support Team]

For a CDECL function doubles are pushed onto the stack by value, 8 bytes.

http://www.programmersheaven.com/2/Calling-conventions

[sapero]

yup, this is correct! thanks

Code Select Expand

extern byte _getch();

class CTest {
   declare int_float_double_int(...);
}

global sub main() {
   CTest c;
   int    idata = 1;
   float  fdata = 1.1;
   double ddata = 1.2;

   c.int_float_double_int(idata, fdata, ddata, idata);
   return _getch();
}

CTest :: int_float_double_int(...)
{
   int vacount;
   #emit mov esi,[ebp+4] ; return address
   #emit mov eax,[esi+2] ; add esp,dword
   #emit shr eax,2       ; dword/4
   #emit dec eax         ; dword=1
   #emit mov [ebp-4],eax ; save in vacount
   print("vacount = ", vacount);

   void *args = va_start(this);
   // note: after *(double)(args+8) - next argument is at args+8+4+4
   print("double: ",
      *(int)(args+0)," ",
      *(float)(args+4)," ",
      *(double)(args+8)," ",
      *(int)(args+16));
   return;
}